This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This massive underground salt mine now holds a sci-fi theme park in its depths.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A marvel of Byzantine engineering under the streets of Istanbul.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

A crumbling hospital from the 1850s on Roosevelt Island.

The very first subway station in New York City is beautiful, decked out in chandeliers, and ... abandoned?

An underground city of salt.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

Once considered one of the country's finest motte and bailey castles.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

Inside this Icelandic greenhouse, geothermal energy keeps tomatoes warm and growing.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Rising from the sea like a stone monster.

Staves, storm-calling, and of course, necropants.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

The most visited, and possibly most controversial, museum in Germany.

This restaurant offers a side of antiques, curios, and a bathroom chock full of owls.